English

Almost quasi-isometries and more non-exact groups

Group Theory 2015-06-30 v1 Metric Geometry Operator Algebras

Abstract

We study permanence results for almost quasi-isometries, the maps arising from the Gromov construction of finitely generated random groups that contain expanders (and hence that are not C*-exact). We show that the image of a sequence of finite graphs of large girth and controlled vertex degrees under an almost quasi-isometry does not have Guoliang Yu's property A. We use this result to broaden the application of Gromov's techniques to sequences of graphs which are not necessarily expanders. Thus, we obtain more examples of finitely generated non-C*-exact groups.

Keywords

Cite

@article{arxiv.1506.08424,
  title  = {Almost quasi-isometries and more non-exact groups},
  author = {Martin Finn-Sell},
  journal= {arXiv preprint arXiv:1506.08424},
  year   = {2015}
}

Comments

11 pages

R2 v1 2026-06-22T10:01:40.691Z